Mitral-specific cardiac damage score (m-CDS) predicts risk of death in functional mitral regurgitation: a study from the National Echo Database of Australia

Aims We set out to explore associations between a ‘mitral-specific’ cardiac damage score (m-CDS) and survival outcomes in mitral regurgitation (MR) and compare the performance of the m-CDS and an ‘aortic-specific’ CDS (a-CDS) in patients with MR within the large National Echo Database of Australia. Methods Among 620 831 unique adults investigated with echocardiography, there were 17 658 individuals (3.1%) with moderate or greater functional MR (aged 76±13 years, 51% female) who met inclusion criteria. A randomly selected cohort of 5000 of these patients was used to test seven different CDS models for prediction of subsequent all-cause mortality during an average 3.8-year follow-up. The best-performing CDS model in the derivation cohort was then applied to a validation cohort of the remaining 12 658 individuals (aged 76±13 years, 51% female). Results The best-performing m-CDS model stratified the full cohort into Stage 0: control (1046 patients, 8%); Stage 1: left atrial damage (3416 patients, 27%); Stage 2: left ventricular damage (3352 patients, 26%); Stage 3: right ventricular damage (1551 patients, 12%) and Stage 4: pulmonary hypertension (3293 patients, 26%). Increasing m-CDS stage was consistently and incrementally associated with both all-cause and cardiovascular mortality at 1 year, 5 years and all-time and remained so after adjustment for increasing age and severity of MR, with a ~35% increase in mortality for each increase in CDS stage (p<0.001). Conclusion A m-CDS was robustly and incrementally associated with short-, medium- and long-term risk of all-cause and cardiovascular mortality in patients with functional MR in this large registry study.